Not a single constituent spoke in favor of the legislation at Kansas gathering

PALCO, Kan.—U.S. Sen. Jerry Moran is usually a reliable supporter of his party’s leadership, but he spent more than an hour Thursday poking holes in the GOP health bill at an overcrowded forum in this town of 278 people.

As more than a hundred of Mr. Moran’s constituents from across the state peppered him with questions about the Senate bill, which he said he would oppose, he outlined a range of concerns, from the severity of its Medicaid cuts to the ways it would affect people with pre-existing medical conditions.